As such a technology, as described in Patent Document 1, an electric supercharger in which a compressor wheel is attached to a rotating shaft and a motor rotor fixed to the rotating shaft is rotated by a motor is known. In the electric supercharger, a ring portion that surrounds the rotating shaft, and a damper and a rolling bearing provided inside the ring portion are provided. The ring portion is attached to the inside of a casing. The damper has a seal such as an O-ring provided on the outer circumferential surface of the rolling bearing, and the outer circumferential surface of the seal is in contact with the inner circumferential surface of the ring portion. The ring portion supports the damper in the radial direction of the rotating shaft.